Why athletes may score low in The Functional Movement Screen (FMS)
Tonicity is the normal tension of a living muscle's elastic fibres. There is a neuromuscular response that determines a person's level of tonicity for everyday movements: Humans has evolved mechanisms in his skeletal muscles that help them deal with gravity and stand up straight. These mechanisms help them move more efficiently and stay stable.
Normal passive muscle tone helps the average person keep their body in a relaxed standing position with minimally increased energy costs and often for long periods of time without getting tired (Alfonse & John. 2008).
These stabilising muscles work every day without being asked. Since the average person doesn't do anything to their body other than move around in a world with a lot of gravity, their level of tonicity isn't as high as the level of tonicity in an elite athlete.
Elite athletes have to deal with high-resistance stressors for hours every day. These stressors cause neural adaptations that make the muscles stronger. The effects of training history and tonicity need to be looked into more. In a training environment, the length of time an athlete has spent training for a sport has a big effect on how well they do in that sport.
As we learn more about neural function and tonicity, we get a better idea of how athletes' bodies change from training and how their bodies work differently from the average person's. What we know about low-threshold and high-threshold muscle contractions can be applied to muscle flexibility and joint mobility (fast twitch and slow twitch activation patterns).
If a muscle contracts on its own without the person wanting it to, it might not be able to fully relax on its own. To help get out of this tonic state, it may be necessary to activate higher threshold motor units on purpose. This will allow the muscle to relax from an involuntary partial contraction. If the resistance from the outside is high enough to meet the involuntary contraction threshold, the muscle contraction changes from one that is done automatically to one that is done by choice.
One of the ideas behind PNF stretching is that this overriding of the nervous system is a good thing. Once a muscle is voluntarily contracted, the tonic state of the muscle at rest usually decreases. This makes the joint range of motion and muscle flexibility better. What does this have to do with a top athlete? If an
If an athlete is asked to do a movement with low resistance, they may test poorly because they are tight. However, if they are tested in an environment with resistances that mimic those in their sport, they may have a very different score (due to an increased level of neural activation). This result shows that the adaptations athletes have that are specific to their sport are likely to make them better at their sport, but they may also lead to a low FMS score and an inaccurate assessment of an athlete's movement quality.
The FMS screen and it’s Relevance within Elite Sport Performance
by Tim Pelot MS, CSCS & Anthony Darmiento BS, CSCS
Masi Alfonse, Hannon John. Human resting muscle tone (HRMT): Narrative introduction and modern concepts, Journal of Bodywork and Movement Therapies, 4:320-332, 2008